The office of the European Union’s foreign policy chief has criticized a decision by a Belarusian court to add further punishments to a sentence against opposition politician Mikalay Statkevich.

Maja Kocijancic, a spokeswoman for the European External Action Service, said on May 6 that the decision to transfer Statkevich to a cell-type prison for allegedly violating prisoner rules was “deplorable.”

Kocijancic described Statkevich as a “political prisoner in Belarus” and said he has suffered “unacceptable treatment" since his arrest in December 2010.

Kocijancic also said “the importance of releasing all political prisoners remains crucial in the context of improving EU-Belarus relations."

Statkevich was found guilty of "organizing mass disturbances" following authoritarian President Alyaksandr Lukashenka's reelection in December 2010.

Statkevich, representing the Belarusian Social Democratic Party, finished with just over 1 percent of the vote in the 2010 poll.